Concrete block

ABSTRACT

An improved concrete block intended to serve as a roadway defining member. The block is in the shape of an elongate concrete body having an essentially triangular cross-sectional configuration with one bottom face and two preferably symmetrical side faces. Each side face is formed closest to the bottom face with a straight threshold portion sloping at a gradient of 1:5, which portion is connected to a second straight portion sloping at a gradient of 1:7 via an essentially circularly arcuate concave portion.

This application is a continuation of application Ser. No. 464,506,filed Jan. 28, 1983, entitled: IMPROVED CONCRETE BLOCK, now abandoned.

BACKGROUND OF THE INVENTION

The subject invention concerns improvements in concrete blocks designedto serve as road barriers, and roadway or lane defining members. Theblocks have an elongate concrete body with an essentially triangularcross-sectional shape including one bottom face and two preferablysymmetrical side faces.

In four-lane traffic routes median barriers and roadway defining membersare often used to prevent vehicles travelling in one direction fromentering the lanes in which the vehicles are moving in the oppositedirection. In case of accidents caused by skidding, aqua-planing, tyrepunctures or careless driving such road barriers may prevent thevehicles involved in the accidents from colliding head-on with oncomingtraffic.

The barriers and roadway defining means usually consist of concreteplinths to which horizontal steel beams are attached. One disadvantagewith barriers and roadway defining members of this kind is that thesteel material of the beams make them somewhat resilient, with theresult that vehicles colliding with the barrier at an oblique angle ofimpact as a rule will be thrown back towards the vehicles travelling ina direction parallel with that of the colliding vehicle, or even bethrown off the road. A comparatively harmless accident therefore mayhave very serious consequences.

Road barriers of the kind referred to above are permanently anchored,that is, they cannot be opened up to allow the traffic to be reroutedonto adjoining traffic lanes in case one lane or roadway is blocked off.Nor is it possible to use this kind of road barriers to protect workmenengaged in temporary road work.

It is also known to use concrete blocks as median barriers to separateopposing traffic roadways. The blocks have a triangular cross-sectionalshape and may be moved temporarily to divert traffic in case ofaccidents and may also be used as protection during road work. Caseshave been reported, however, when as a result of aqua-planing orskidding, vehicles hit a row of concrete blocks at an acute angle androll over the blocks and onto the lane of oncoming traffic, thus causingserious accidents. Also when vehicles hit the concrete blocks at lowspeeds the damages to the front part of the car chassis have proved tobe so serious that the car has to be towed from the place of accidentand be repaired at great expense.

The purpose of the road block in accordance with the subject inventionis to prevent vehicles hitting the barriers from rolling over thebarriers, from being thrown into the lane of parallel traffic or frombeing damaged to such an extent that the vehicle must be towed away. Theroad block is furthermore intended for use in temporary road work. It isalso designed to allow individual, damaged blocks to be easily replaced,to allow water runoff, and to be rapidly and easily dismantled andremoved for asphalting and other paving work or when an opening isdesired through the barrier. The block in accordance with the inventionfurthermore serves as a blind, screening off glaring and blinding lightsfrom oncoming traffic. In addition, it is designed to allow road signs,lights poles and noise-reducing mats to be mounted thereon.

SUMMARY OF THE INVENTION

To achieve these purposes, the block in accordance with the subjectinvention is characterised in that each side face of the block is formedin the area closest to the bottom face with a straight threshold portionsloping at a gradient of 1:5, said portion being interconnected to asecond straight portion sloping at a gradient of 1:7 via an essentiallycircular arcuate concave portion.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in closer deetail in the following withreference to one embodiment thereof illustrated in the accompanyingdrawings, wherein

FIG. 1 is an end view of a concrete block in accordance with theinvention,

FIG. 2 is a broken view of two blocks in accordance with the inventionwith means for interlocking these two blocks together, and

FIG. 3 shows two interlocked blocks.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

The concrete block 1 is supported on feet 3 formed on a bottom face 2,said feet being provided to allow water to flow freely underneath theblock. The side faces 4 have a profiled shape incorporating a lowerstraight threshold portion 5, a concave arcuate portion 6 and an uppersloping portion 7 on either side of the block.

The gradient of the slope of the threshold portion 5 is 1:5. It isdesigned to turn the front wheel of a vehicle hitting the block at asmall angle of impact in a direction in parallel with the lengthwiseextension of the barrier. As a result, the vehicle will continue itstravel alongside the barrier of concrete blocks without being damaged orcausing serious accidents.

When the angle of impact of the vehicle is larger and the speed higherthe vehicle will "climb" over the threshold portion 5 up onto theconcave arcuate portion 6. This will consume some of the kinetic energyof the vehicle. When the angle of impact is large the vehicle will"climb" high up onto the sloping portion 7 the gradient of which is 1:7,and the majority of the kinetic energy of the vehicle will then beconsumed. However, the deceleration is not so abrupt that vehiclesbehind run the risk of driving into the vehicle colliding with thebarrier, which might otherwise have resulted in a chain of collisions.

When it is "climbing" up the barrier the vehicle will automatically beguided in a direction in parallel with the barrier and the rear wheel ofthe vehicle will follow the front wheel up onto the barrier. In theinitial phase a considerable amount of the kinetic energy will beabsorbed by the tyres and the suspension of the vehicle. A furtheramount of the energy may be absorbed through the concrete blocks becausethe latter, being interlocked into a long chain forming the barrier, maybe displaced somewhat laterally on the feet 3.

The means for interlocking the blocks 1 to one another are shown in FIG.2 and comprise a tube 8, a retaining plate 9 and two nuts 10. At eachend the concrete blocks 1 are provided with a centrally located andvertically extending groove 11. The groove 11 terminates short off thebase face 2 of the block and is provided at its lower end with avertically extending pin 12 which is directed upwards. When two blocks 1have been placed end-to-end the two grooves 11 of adjoining blockstogether form a channel in which the tube 8 may be inserted from above.When the tube 8 is inserted fully into the channel it encloses the twopins 12 which are connected with reinforcement irons 13 cast into theblock. At the upper end of the channel and spaced from the latter thereis provided a threaded pin 14, one adjacent each side face of the block.The retaining plate 9 is formed with apertures 15 matching the pins 14and the plate may be locked to the latter with the aid of the nuts 10.Each end face of the blocks is slightly bevelled, which allow theblocks, being interconnected at the centre line, to be locked togetheralong the radius of a curve.

The interlocking means in accordance with the invention are capable ofwithstanding considerable stress without breaking while at the same timethey allow interlocked blocks to be rapidly and easily disconnected fromone another. Road signs, light poles and noise-reducing mats may bemounted at the interlocking means.

The concrete blocks in accordance with the subject invention have beentested by the Swedish National Road and Traffic Research Institute(VTI). The tests show that vehicles colliding with a barrier formed byblocks in accordance with the subject invention as a rule may be drivenaway from the place of the accident without further. Only in cases ofextremely heavy collisions is it necessary to tow the vehicle away.However, not even when the impact from the vehicle colliding with thebarrier is extremely strong has one been able to detect any tendenciesin the colliding vehicle to bounce away from the barrier in a directiontowards the cars travelling in parallel lanes or to roll over thebarrier and into the lane of the oncoming traffic.

The invention is not limited to the embodiment described in theaforegoing but various modifications are possible within the scope ofthe appended claims. For instance, the height and width dimensions ofthe concrete blocks may differ, the essential feature of the inventionbeing the provision in the block of a lower straight threshold portionsloping at a gradient of 1:5, a concavely arcuate portion 6 and an uppersloping portion 7 the gradient of which is 1:7. Other interlocking meansthan those shown to link the blocks to one another are possible.

What we claim is:
 1. In a non-anchored barrier to be used on the groundsurface along a roadway adjacent a lane thereof for partially consumingmomentum of a vehicle driven against it while deflecting the vehicleback into the lane and causing it thereafter to be confined within apath generally parallel to the barrier and generally within the lane,the combination of:a plurality of elongate concrete blocks arrangedalong a path defining the barrier, each block being of generallytriangular configuration in cross-section to define, on at least thatside thereof exposed to traffic and in the lowermost region of thatside, a substantially flat, inwardly inclined threshold surface meanshaving a height extending above the ground surface and an inclinationsufficient for resisting climbing of a vehicle front wheel over saidthreshold surface means while turning the front wheels of a vehicle in adirection parallel with the barrier when a vehicle front wheel strikesthe block at a small angle or low speed, upper surface means including aconcave arcuate surface smoothly joining said inwardly inclinedthreshold surface means for further consuming momentum of the vehicleand allowing a rear wheel to follow the striking front wheel onto saidupper surface means when a vehicle front wheel strikes the block in afashion sufficient to climb over said inwardly inclined thresholdsurface means; and means for coupling the blocks into a chain capable offlexure to consume a still further amount of momentum of the vehiclethrough lateral weight displacement of adjacent blocks along the chainparticularly when the vehicle climbs said inwardly inclined thresholdsurface means; said blocks being disposed in end-to-end relation withadjacent blocks having substantially contiguous end surfaces, said endsurfaces being vertically grooved from adjacent a bottom portion of anassociated block to adjacent a top portion of an associated block sothat said end surfaces define a cylindrical channel of substantiallycircular cross-section, said means for coupling comprising tube meansreceived in said channels for preventing relative movement betweenblocks while effecting transmission of lateral and rotational forcesfrom one block to the next, pin means received in a bottom end of eachof said tube means for resisting longitudinal separation between saidbottom portions of the blocks, and means joining adjacent blocks at thetop portions thereof for resisting longitudinal separation between saidtop portions of the blocks and for blocking an upper end of each channelto retain said tube means longitudinally within its associated channel.2. In a non-anchored barrier to be used on the ground surface along aroadway adjacent a lane thereof for partially consuming momentum of avehicle driven against it while deflecting the vehicle back into thelane and causing it thereafter to be confined within a path generallyparallel to the barrier and generally within the lane, the combinationof:a pair of concrete blocks disposed in end-to-end relation and havingsubstantially contiguous end surfaces, said end surfaces beingvertically grooved from adjacent a bottom portion of an associated blockto adjacent a top portion of an associated block so that said endsurfaces define a cylindrical channel of substantially circularcross-section, each block being of generally triangular configuration incross-section so as to form a portion of said barrier; tube meansreceived in said channel for preventing lateral and rotational relativemovement between said blocks while effecting transmission of lateral androtational forces from one block to the other; pin means received in abottom end of said tube means for resisting longitudinal separationbetween said bottom portions of the blocks, and means joining saidblocks at the top portions thereof for resisting longitudinal separationbetween said top portions of the blocks and for blocking an upper end ofsaid channel to retain said tube means longitudinally within saidchannel.
 3. In a non-anchored barrier as defined in claim 2 wherein saidpin means is in the form of a member having a generally horizontalportion embedded in the concrete of its associated block and anupstanding portion received in the tube means.
 4. In a non-anchoredbarrier as defined in claim 3 wherein the means last mentioned comprisesan anchor member embedded in and upstanding from each block and a plateconnecting said anchor members.
 5. In a non-anchored barrier as definedin claim 2 wherein each block defines, in the lowermost region thereof,a substantially flat, inwardly inclined threshold surface means having aheight extending above the ground surface and an inclination sufficientfor resisting climbing of a vehicle front wheel over said thresholdsurface means while turning the front wheels of a vehicle in a directionparallel with the barrier when a vehicle front wheel strikes the blockat a small angle or low speed, upper surface means including a concavearcuate surface smoothly joining said inwardly inclined thresholdsurface means for further consuming momentum of the vehicle and allowinga rear wheel to follow the striking front wheel onto said upper surfacemeans when a vehicle front wheel strikes the block in a fashionsufficient to climb over said inwardly inclined threshold surface means.